The existing thermostat wiring is 4 wire. 2 red for power (it says line) and 2 black for load. There are white and ground wires in the wall, but are not connected to the thermostat, so I think I only need to worry about the 2 red and 2 black that are connected. Do I only need to use 1 red and 1 black to connect to the honeywell or do I need to wire both reds with 1 black on the honeywell and both blacks with the other black on the honeywell? If I just need the 1 red and 1 black, do I wire the other red and other black together?

THANK YOU. The honeywell wiring diagram makes absolutely no sense to me.

Page one follow 4 wire. You may have to sound out the wiring with a meter because it depends upon which legs are hot and which goes to the heater. There will be a pair of wires a possible combo of one red and one black that will be 220 volts but I would test with a meter. Click on link

http://customer.honeywell.com/techlit/pdf/69-0000s/69-1855.pdf

Just connect the two red lines together and then connect each lead from the thermostat to the 2 black wires. One to One.